And they’re not alone. The Centers for Disease Control and Prevention has been tracking another, unrelated Chipotle food poisoning outbreak in California, Illinois, Maryland, Minnesota, New York, Ohio, Oregon, Pennsylvania and Washington, in which victims have been as young as one year and as old as 94. Using whole genome sequencing, CDC investigators identified the DNA fingerprint of the bacterial culprit in that outbreak as E. coli strain STEC O26, which was found in all of the sickened customers tested.

Outbreaks of food poisoning have become something of a Chipotle trademark; the recent ones are the fourth and fifth this year, one of which was not disclosed to the public. A particularly worrisome aspect of the company’s serial deficiencies is that there have been at least three unrelated pathogens in the outbreaks–Salmonella and E. coli bacteria and norovirus. In other words, there has been more than a single glitch; suppliers and employees have found a variety of ways to contaminate what Chipotle cavalierly sells (at premium prices) to its customers.

“We may be at a higher risk for food-borne illness outbreaks than some competitors,” the company admits in its filings with the Securities and Exchange Commission, “due to our use of fresh produce and meats rather than frozen, and our reliance on employees cooking with traditional methods rather than automation.” (Think about that: Would you agree to open-heart surgery if the anesthesiologist planned to use “traditional methods” instead of state-of-the-art technology?)

One wonders whether Chipotle’s “traditional methods” include employees’ neglecting to wash their hands before preparing food, which is how norovirus is usually spread. And the fresh versus frozen dichotomy is nothing more than a snow-job. Freezing E. coli-contaminated food does not kill the pathogens; it preserves them. (During my laboratory research days, we stored viruses and bacteria in ultra-low-temperature freezers.)